I submitted 3 apps to windows market place for windows phone 7. I learned many things about submitting apps to windows market place. It (currently) takes 4-5 days to check your app after you submit it to windows market place. So here are some points, should be cleared to avoid rejection of your app.

1. Tile! : When you deploy your app in your physical phone [and not in emulator] hold tap on application name, select “pin to start”. Check if the icon is not default and is what you chose for your application. Second, that name should not be XAP file name, it should be your application name.
2. Snapshots: When taking snapshot of your application using emulator, emulator chrome must not be visible in snapshot.
3. Theme change: Change theme from “Dark” to “Light” and vice versa and check if your content is visible or not. Check textbox and button about their behavior.
4. Exceptions: Your application must be able to handle (catch) any kind of exception thrown during execution.